This was a prospective randomized, controlled trial designed to quantify the reduction in cost and length of stay of early discharge of emergency department patients evaluated for acute myocardial infarction, who are deemed to be low risk based on a modified HEART score (a score that incorporates troponin biomarker, ecg, patient characteristics, and physician clinical judgment).

This was a prospective randomized, controlled trial conducted from February 2014 to May 2015 designed to quantify the reduction in cost and length of stay of early discharge of emergency department patients evaluated for acute myocardial infarction, in those deemed to be low risk based on a modified HEART score. Our study enrolled only those deemed low risk, as these are the patients we believe best served by utilization of the HEART score decision aid.

A total of 105 patients evaluated for AMI in the ED with a modified HEART score ≤ 3 (which includes cardiac troponin I < 0.04 ng/ml at 0 and 3 hours) were randomized to immediate discharge (n = 53) vs management in an observation unit with stress testing (n = 52).

The primary endpoints were 30-day total cost and length of stay. Secondary endpoints were all-cause death, nonfatal AMI, rehospitalization for evaluation of possible AMI, and coronary revascularization at 30 days.

That such an early discharge strategy would decrease cost and length of stay is intuitively expected; our goal was to quantify such a reduction.

Inclusion Criteria:

• patients 21 years or older
• patients who presented to the Emergency Department with symptoms suspicious for AMI.
• patients for whom the ED physician's intention to send the patient to the observation unit for stress testing

Exclusion Criteria:

• Cardiac Troponin I > 0.04 ng/mL at 0 or 3 hours
• clinical presentation warranting admission
• inability or unwillingness to consent
• trauma as etiology of presenting symptoms.